Files can be opened for reading, writing, or both. The Linux kernel also employs a cache, called the dentry cache, to store the results of directory resolutions, providing for speedier lookups in the future given temporal locality. Each command comes with a manual page which can be used to learn …

A disk drive consists of one or more platters, each made of finely polished glass or ceramic composites and coated with a fine layer of iron oxide. Freedom to choose. A block device cannot transfer or access a unit of data smaller than a sector and all I/O must …

With Linux and open source, IT is now far more transparent to the broader enterprise, helping to better align with general business goals and actually innovate as opposed to just maintaining a status quo. The ease with which you can control the inner workings of Linux is another attractive feature …

Computer software was almost universally regarded as being akin to mathematics, i.e., something that anybody is permitted to use in any amount, with any desired modifications and for whatever purpose desired. However, there is a fundamental difference: free software retains its copyright and is released under a license, whereas …

So what do I mean by transparent? Disk drives provide a more permanent method for storing data, keeping it on spinning disk platters. Like MINIX, it could uncharitably be described as a "toy" example of its kind-the MINIX filesystem could handle filenames only up to 14 characters and address only …

For example, a process may have to wait for a character to be read from a file. Loadlin works from a DOS command line, killing DOS and invoking Linux. Character devices are accessed via character device files. These operations start at a specific byte, which is one's conceptual "location" within …

We can also easily jump back to the GUI when it suits us. This system call creates a duplicate of the calling process. Unix systems historically did not include many higher-level abstractions. If the kernel handles the signals, it will do the default actions required for this signal.

Linux adventures …

For copying files, for example, you need to download another tool when you use Windows. This can be extremely useful if the output or calculation you require consists of multiple commands, and it will be expected multiple times throughout the script execution. There are several good reasons for becoming familiar …

The Unix philosophy recommended utilizing small, purpose-built programs in combination to do complex overall tasks. An exit status of zero indicates success. Dynamic new technologies such as the Java technology and XML run swimmingly on Linux, as do any number of more esoteric programming languages, from Logo and Rebol to …

Linux keeps looking through the pending list from the start until there is a pass where no semaphore operations can be applied and so no more processes can be woken. For example 128 or 512 bytes, even if the device driver asks for less. For developers, opening one's mind to …

A partition is a large group of sectors allocated for a particular purpose. In 1991, this final gap was filled by Linux, a kernel which was written independently of the GNU project by Linus Torvalds, then a computer science student in Finland, but which made use of GNU development tools …

Because of POSIX standards and compliance, software written on Unix could be compiled for a Linux operating system with a usually limited amount of porting effort. When the process resumes operation it appears as if the signal handling routine were called normally. They will be the "power users" and the …

If a developer needs a VM or if IT Ops needs to provision a server, they expect to do so quickly and painlessly; Linux's scalability allows for this rapid provisioning, as does its lack of cost-prohibitive licensing. These processes are said to be in the foreground. The file position starts …

Keep in mind that these are only conventions---not rules. In fact, the current cloud functions-as-a-service (FaaS)/serverless computing model owes much of its heritage to the Unix philosophy. This chapter describes how Linux supports the network protocols known collectively as TCP/IP. Remember that the shell is a program providing …

Each command comes with a manual page which can be used to learn about its function as well as what options and arguments each specific command accepts. Before I became involved in Free Software, I had far different opinions, ideas, and beliefs than I do today. A security breach unnoticed …

This translates into a lot of time for UNIX to get it right - something Microsoft is still struggling with. So, /dev/hda2, the second partition of the primary IDE disk has a major number of 3 and a minor number of 2. If you tried to code up something similar …

If a parent process terminates before its child, the kernel will reparent the child to the init process. The takeover of software by corporations continued at a rapid pace, and free software was becoming an endangered species. Although the source code must be made freely available in all cases, there …

For the purposes of the shell, a command which exits with a zero exit status has succeeded. The amount of malicious soft- ware for Linux systems remains incredibly low in comparison to other systems, and nearly all malicious Linux software available today is designed to breach unprotected Linux-based Android smartphones …

Sometimes the DMA channel for a device can be set by jumpers; a number of ethernet devices use this technique. The control bus contains various lines used to route timing and control signals throughout the system. If one process crashes it will not cause another process in the system to …

The term “emotional support animal” is in the news at present, mainly, sadly, because of its predictable abuse. In Japan, companion animals are petto or aigando butsu, animals to love, or play with, or take pleasure in, which just about covers it all. The next time you greet your own …

To kill rhinos, Mozambican poachers appear to prefer hunting rifles over other firearms available to them. There is evidence that Czech CZ 550 bolt-action rifles have become more popular with poachers in recent years. While obtaining a rifle through official channels in Mozambique can take up to six months, there …

While Colombia is a special case in some ways because of its long history of conflict, extractive industry activities in less extreme settings are increasingly marked by the presence of private, corporate security. The result is a variety of collaborative partnerships between public and private, formal and informal types of …

To help bring order to chaos, standards groups codify system interfaces into official standards. The number of bytes that the device driver requests is rounded up to the next block size boundary. To those who believe that even bad attention is better than no attention, being treated as a non-entity …

For instance, containers have largely evolved through community involvement. There are three types of partition supported by fdisk, primary, extended and logical. Any of the bytes within a file may be read from or written to. The answer is that you can use any method you like to refer to …

Disk drives provide a more permanent method for storing data, keeping it on spinning disk platters. By contrast, most software carries fine print that denies users these basic rights, leaving them susceptible to the whims of its owners and vulnerable to surveillance. The majority of those working on Free Software …

Recently DBMS Superpower Sybase made their Adaptive Server Enterprise technology available on the Linux platform. The takeover of software by corporations continued at a rapid pace, and free software was becoming an endangered species. When a user logs in, the login program checks the username and password, and then starts …

This, in turn, allows for the use of the pathnames with which all Unix users are familiar-for example, /home/blackbeard/concorde.png. I think Linux is more a state of mind. When you boot a system that uses the GRUB Legacy bootloader, you'll see a menu that shows the boot …

The most common disks used in Linux systems today are Integrated Disk Electronic or IDE disks. This is because IP addresses are simply an addressing concept, the ethernet devices themselves have their own physical addresses. The LSB extends POSIX and SUS, and adds several standards of its own; it attempts …

It would not be enough to stop here, though. OSS is developed by those people who have a use for it. TCP/IP is so entrenched that Windows implemented it. Shell scripts are not unlike Windows batch files for controlling the system, but a lot more powerful.

Learn how I …

Why make it easier for them. Linux supports three types of hardware device: character, block and network. For Linux, a vendor can create a device driver for a specific hardware device and expect that, within reason, it will operate across most distributions. They should be given the opportunity to examine …

Its latest releases often inspire the other Linux distributions to adopt new features and make changes. Any site that is requested through the "what's that site running" query form at Netcraft.com is added to the set of sites that are routinely sampled; Netcraft doesn't routinely monitor all 22 million …

and insert it as the first line of your script. Some people, particularly members of the Free Software Foundation, refer to this collection as GNU/Linux, because many of the tools included are GNU components. These categories determine what powers are available to a user. Unlike Windows, Linux requires each …

Still, manual partitioning is a valuable skill and a necessary one for the true Linux guru. It is time for the opening of the tools that will be needed to build this new age. Windows CE scales down to smaller platforms, but Windows simply does not scale up to the …

An inode stores metadata associated with a file, such as its modification timestamp, owner, type, length, and the location of the file's data-but no filename! Sed, as you saw in our example, is basically used for altering a text file without actually having to open it up in a traditional …

However, Linux does not require the use of such Anti-Virus programs. The kernel modules are linked object files just like other programs in the system except that they are linked as a relocatable images. For many people, the next step will be to carefully read a good introductory book on …

None other than the system call handler! The shell program is what presents the prompt and accepts subsequent commands. If you want to use Linux as a platform for a very advanced application or application set, you will be interested in aspects of the system such as kernel hacking, the …

The software that handles or manages a hardware controller is known as a device driver. The platters are attached to a central spindle and spin at a constant speed that can vary between 3000 and 10,000 RPM depending on the model. We can access the database from other programs …

One more thing, if you don't want your programming Linux distro to be devoid of systemd, there's an OpenRC spin for that. Thanks to Linux and the broader world of open source, this methodology becomes clearer and easier to implement on an almost daily basis, as new Linux-based innovations, like …

As it's compiled from RHEL sources, most of the commercial software built for RHEL can be made to run on CentOS. Initially, there is only one directory on the disk, the root directory. But the Linux community is much more than the kernel, and needs contributions from lots of other …

The list goes on. Although the terms free software and open source software are usually used more or less interchangeably, there are some subtle differences. Advocates of copyleft respond by pointing out that there is no such thing as absolute freedom. So, the FAT module contains a reference to the …